Herman Cain's call for an investigation into President Barack Obama's decision to no longer defend a federal ban on gay marriage has riled the National Organization for Marriage (NOM).

The Republican presidential candidate said during a conference call with reporters last week that the Obama administration's position to no longer defend in court the Defense of Marriage Act (DOMA), the law that forbids federal agencies from recognizing the legal marriages of gay and lesbian couples, was an impeachable offense.